Unique to the Mac version is support for Apple's multi-touch trackpad shipping with every model of MacBook since early this year.

Although it's no sure thing multi-touch gestures will ship with the public release of Firefox 3.1, as they stand, Mozilla's native trackpad gestures outdo what's presently available in Safari.

Native multi-touch gestures supported by 3.1 Beta 2 are:

Swipe up: top of the page
Swipe down: end of page
Swipe left: back in browser's history
Swipe right: forward in browser's history
Pinch together: zoom in
Pinch apart: zoom out
Twist left: previous tab
Twist right: next tab

There's no set date for the public debut of Firefox 3.1, although Mozilla says to expect a third beta before the final release. ®